Recent years have seen miniaturization of electric and electronic appliances, and under such trends, magnetic cores used in transformers and coils of electric and electronic appliances have been required to achieve various properties such as high permeability at high frequencies and low eddy-current loss. Magnetic cores used therein are thus required to have high resistance so that the eddy-current loss is low in the high-frequency band. One example of such magnetic cores is a powder core formed by compacting magnetic fine particles each coated with an insulating coating. Compared to when a bulk magnetic material is used, a powder core has low permeability but the resistance can be significantly increased and the eddy-current loss can be significantly decreased.
An example of a method for obtaining a powder core known in the art is a method that includes mixing two or more amorphous soft magnetic alloy powders having different average particle diameters and a low-melting-point glass, coating the resulting mixture with an insulating binder resin, compacting the resulting coated mixture to form a compact, and annealing the compact at a temperature lower than the crystallization temperature (for example, refer to Japanese Unexamined Patent Application Publication No. 2010-141183).
Also known is a method for producing a magnetic layer material by mixing a glass powder with a metal magnetic powder having a core-shell structure (for example, refer to Japanese Unexamined Patent Application Publication No. 2013-33966).
A multilayer coil component that contains a non-silicate glass and a metal magnetic powder is also known (for example, refer to Japanese Unexamined Patent Application Publication No. 2014-236112).
Coil components such as one described above do not have sufficient dielectric strength and their core loss has not been satisfactorily low. Development of coil components with higher dielectric strength and lower core loss has been eagerly anticipated.